Computerized tomographic colonography after cathartic preparation and colonic distension.
Sensitivities for the detection of lesions 10 mm or more range from 32% to 90% depending upon the skill of the reader.
Detection of colorectal polyps and cancer approaches that of conventional colonoscopy.
CT colonography considered a valid alternative to colonoscopy for screening for colorectal cancer in the general population.
In an evaluation of 937 patients with 1-3 risk factors for colorectal cancer patients underwent CT colonography followed by colonoscopy on the same day and the virtual colonoscopy had an 85% sensitivity and 88% specificity for detecting advanced neoplasia (Regge).
Threshold for detection of a lesion 5 mm.
Pickardt and others evaluating 1233 asymptomatic patients revealed that three dimensional endoluminal display can achieve a 93.8% sensitivity and 96% specificity for polyps of at least 10 mm in diameter compared to colonoscopy.
Optical CT colonography misses 2-12% of polypoid lesions larger than 10 mm (Lieberman).
Advantages over conventional colonoscopy include less invasive, less costly, more safe, and equally sensitive for relevant pathology.
Drawbacks include continued need for cathartics and lack of therapeutic capabilities.